Mirena coil is a hormonal IUD. Is a T-shaped Plastic device that is inserted into the womb. It releases miniscule amount of progesterone which acts on the lining of the wombs locally. The systemic absorption of this hormone is very small comparing to tables and pills. Mirena is inserted by your doctor. It can stay in for 5 years. It’s a very effective form of contraception. It can also be used to treat heavy periods. Insertion may be uncomfortable but removal is very quick and easy. The thread of the coil passes through the cervix into the vagina which can be pulled out by your doctor at the office.